The present invention relates, in general, to surgical instruments for retrieving tissue and, more particularly, to endoscopic surgical instruments such as pouches or specimen retrieval bags for the removal of tissue through a small incision.
Endoscopic surgery is a procedure wherein surgery is performed through a series of small openings or incisions in a patient. This type of surgery reduces or eliminates the need for large incisions and has changed some of the major open surgical procedures such as gall bladder removal to simple outpatient surgery. Consequently, the patient""s recovery time has changed from weeks to days. These types of surgeries can be used for repairing defects or for the removal of diseased tissue or organs from areas of the body such as the abdominal cavity.
Of interest is the removal or excision of biological material or tissue from the body through a small opening such as an incision, a small natural orifice, or through a small diameter Laparoscopic access port such as a trocar. Tissue can have many types or forms but fall into three general categories: firm tissue such as muscle and solid tumors, soft tissues such as liver, and fluid filled tissues such as a cyst, a gall bladder, a spleen, or an inflamed appendix. Some tissue can be a mix of multiple categories. For example, an inflamed gall bladder can be a mix of hardened gallstones, fluids such as bile and pus, and an outer covering of firm tissue.
One challenge that exists with minimally invasive surgery is the removal of the excised tissue through the small opening. A time-honored solution is the manual cutting of the large tissue mass into small pieces that can fit through the opening. However, with this process fragments of tissue can be dropped and fluids can be spilled into the body cavity. This can cause complications if the excised tissue is cancerous or infected such as the seeding and re-spreading of cancer, or the spreading of an inflammation to healthy tissue.
In answer to the above challenges, surgical pouches or specimen retrieval bags were developed. The specimen retrieval bags are placed into an inner cavity of the body, the bags are opened, and the diseased tissue is placed within. The specimen retrieval bags are then closed to prevent the migration of tissue and fluids from the bag into the inner cavity of the body. After placing diseased tissue into the open specimen retrieval bag, the bag is closed and pulled from the opening in the patient. Drawstrings are typically used to close the specimen retrieval bag in the body and to draw the bag out of the opening in the body.
The small opening has forced several interesting design challenges to the makers of the specimen retrieval pouches. That is, the specimen retrieval pouches must be tightly rolled up or constrained to fit into the small opening within the patient, and fully opened or unfurled when deployed within the patient. To accomplish the above goals, a surgical deployment instrument was created. The surgical deployment instrument contains a tightly rolled or constrained specimen retrieval bag and a deployment mechanism that ejects and opens the bag from the distal end of the instrument. The surgeon activates the deployment mechanism by pushing on a deployment lever once the specimen retrieval bag is within the patient. Metallic spring arms are generally used to push the tightly rolled bag from the surgical deployment instrument and to spread open the opening of the bag. The excised tissue is placed into the open specimen retrieval bag, and the bag is closed by simultaneously detaching the bag from the spring arms and closing the opening of the bag with a drawstring. The spring arms are withdrawn back into the surgical deployment device by pulling the deployment lever back out of the surgical deployment instrument. The captured tissue is removed from the opening within the patient by pulling on the drawstrings to withdraw the specimen retrieval bag from the patient. Surgical instruments of this type are well known in the art and are described in U.S. Pat. No. 5,465,731 by Bell et al. , in U.S. Pat. No. 5,480,404 by Kammerer et al. , and in U.S. Pat. No. 5,647,372 by Tovey et al. which are incorporated herein by reference.
Specimen retrieval instruments have a specimen retrieval bag that is used to hold excised tissue. The specimen retrieval bags are generally held in an elongated support tube in a constrained condition. The specimen retrieval bag is inserted into the patient in the constrained state and the surgical retrieval instrument is fired to eject the bag from the elongated support tube and deploy it in an open state. Excised tissue is inserted into the open specimen retrieval bag and the bag is closed and detached from the specimen retrieval instrument. The fired specimen retrieval instrument and filled specimen retrieval bags are removed from the patient separately. Specimen retrieval instruments are well known in the art such as those described by Kammerer et al. in U.S. Pat. No. 5,480,404 and by Rousseau in U.S. Pat. No. 5,971,995, both of which are hereby incorporated by reference.
Whereas the above specimen retrieval bags and surgical deployment mechanisms worked well, in some cases, a surgeon could inadvertently partially activate the bag deployment mechanism and partially deploy the bag from the instrument. When the surgeon attempted to correct the mistake by de-activating the deployment mechanism, the bag could be partially detached from the metallic arms and fail to open properly. The partially opened bag, in some cases, was unusable and could require a replacement surgical instrument. To address this issue, motion control mechanisms or one way ratchet mechanisms can be incorporated with the surgical deployment instrument. Dual one way ratchet mechanisms are taught in U.S. Pat. No. 5,971,995 by Rousseau, each ratchet mechanism being fully engaged at all times. One ratchet mechanism limits proximal motion and one ratchet mechanism limits distal motion. Three nested and telescoping elements are provided, with two elements, one of which is the deployment lever, moving into the instrument to deploy the bag and one element, the deployment lever, moving out of the instrument to close and release the specimen retrieval bag. One ratchet mechanism limits travel of one of the two elements moving into the instrument and the second ratchet mechanism limits movement of the deployment lever moving out of the instrument. However, the dual ratchet mechanisms of the Rousseau device cannot prevent the surgeon from partially inserting the deployment lever and partially withdrawing the deployment lever. These actions can partially deploy the specimen retrieval bag from the surgical instrument.
What is needed is a simple low cost surgical deployment instrument that offers all of the advantages listed above and overcomes the needs described above. Thus, it would be advantageous to provide an improved simple motion control mechanism or ratchet mechanism that prevents the partial deployment of the specimen retrieval bag. . Presently, there are no known surgical deployment instruments that can provide the surgeon with the improvements and benefits described above.
In accordance with the present invention, there is provided a surgical instrument for retrieving tissue from a patient. The instrument includes an elongated support tube having a proximal end and a distal end, and an elongated inner rod slidably and coaxially disposed within the support tube. The rod has a removable pouch attached thereto, wherein the pouch is initially disposed within the support tube, and wherein distal movement of the rod ejects the pouch from the tube. The instrument further includes a mechanism engaging the rod such that after the rod has initially been moved distally, the mechanism prevents proximal motion of the rod. The mechanism disengaging upon total ejection of the bag from the tube, and thereafter allows proximal and distal movement of the rod.